Hybrid Solar Plant with Synchronous Power Controllers Contribution to Power System Stability

The penetration of renewable power plants in the global electricity mix is reaching significant levels, and power system operators are adapting their grid codes, so that renewable generators do not alter the operation of the grid, preventing the introduction of additional disturbances and contributing to the control of the power system. In this context, hybrid solar plants arise as a tradeoff solution that combines the ability of solar thermal energy plants to smooth the solar resource variations and to generate a certain amount of power when there is no sun, with cheaper and easier to build and control solar photovoltaics, with the aim of providing grid-friendly, clean, renewable energy at a minimum cost. This paper analyzes the impact that a hybrid solar plant has on a power system when its PV conversion system employs advanced controllers that further contribute to a harmonious interaction between the solar resource and the grid. The analysis compares the results obtained by the hybrid plant in different operating conditions with the performance of a purely solar thermal energy plant of a similar size, and the results prove that the utilization of PV is beneficial for the power system, increasing the damping of oscillations, mitigating frequency excursions, and reducing the effort done by other generating units in the system when severe disturbances take place.